1. Field of the Invention
The present invention is related to the field of fork lifts and fork lift carrier vehicles. More specifically, the invention relates to a mounting system for mounting a vehicle mounted forklift on a carrier vehicle.
2. Description of Related Art
In industry, forklifts are frequently used to load and unload stacked pallets of products from tractor trailers that transport the pallets of products to the desired location. In certain situations, a forklift may not be available at a particular location for unloading the tractor trailer. Of course, a forklift may also be transported to the desired location together with the tractor trailer so as to eliminate such a problem of unloading. However, sending a transport vehicle with a forklift adds additional expense to the total cost of transporting the pallets of products to the desired location. One alternative is to have the tractor trailer transporting the pallets of products transport the forklift to the desired location as well. However, transporting the forklift on the bed of the trailer is not desirable because it takes up much need room on the bed thereby reducing the capacity for transporting the pallets of products.
In response, various mounting systems and methods have been devised for transporting the forklift so that it can be transported to the desired location without reducing the capacity for transporting the pallets of products on the bed of the trailer. U.S. Pat. No. 4,266,795 to Walker discloses a forklift towing structure including a pair of pivotable levers attached to a base of a mast that is used engage a crossbar on the trailer thereby allowing the forklift to be towed by the trailer. However, the forklift towing structure disclosed in Walker has been found to be an inadequate solution for a variety of reasons. First, the towing structure of Walker requires a hydraulic cylinder to actuate the pivotable lever and to lift the front wheels of the forklift. Of course, such added mechanisms substantially increases the cost of the forklift. In addition, because the pair of pivotable levers are mechanically hinged, the bushings of the levers invariably have tolerances and wear rapidly due to the heavy weight placed thereon. Moreover, the forklift is often unstable when towed since it lacks a suspension suitable for high speed highway use. For the above reasons, the towing structure of Walker has not gained wide use in industry.
A more recent alternative solution has been proposed where the forklift is not towed by the trailer, but instead, is fully lifted and mounted to the end of the trailer using the lift features of the forklift itself. For instance, U.S. Pat. Nos. 5,575,604, 5,813,820 and 6,024,535 all to Dubosh et al. discloses an apparatus and method for mounting a forklift on a carrier by lifting the forklift on to the end of the trailer using the forks of the forklift. Dubosh et al. discloses that the apparatus includes crossbars provided on the frame of the forklift that engages pivotal latches provided on the trailer. In use, the mast of the forklift is first advanced slightly and the carriage is raised to a level so that the forks are aligned with the pockets provided on the trailer. The forklift is then moved toward the trailer so that the forks are received within the pockets. The carriage of the forklift is then lowered on the mast thereby lifting the forklift from the ground into a position where the bars are above the pivotal latches. The mast is then retracted so that the crossbars on the frame of the forklift are directly over the latches and the carriage is then raised causing the forklift to be lowered until the crossbars engage the latches of the trailer. The invention of Dubosh has been found to provide secure mounting of the forklift to the end of the trailer without reducing the capacity for transporting pallets of products on the bed of the trailer.
In use however, various limitations and disadvantages of the apparatus of Dubosh has been found by the present applicant. In particular, it has been found that the apparatus of Dubosh is somewhat cumbersome and difficult to use. In particular, because the forks are pivotable (tiltable) with the mast and also vertically displaceable within the mast, the operator mounting the forklift to the trailer must manipulate both of these mechanisms to properly align the bars on the frame of the forklift to the latches on the trailer. Because of the degrees of relative motion possible, such alignment is difficult to attain quickly and consistently. In addition, another disadvantage in the apparatus of Dubosh is that during the mounting procedure, the forks must be advanced a relatively large distance causing large stresses and strains on the various components of the lift and advancing mechanisms as they support the weight of the forklift in this extended position, at least until the carriage is retracted. Furthermore, because the latches are provided on the frame of the forklift, concentrated forces caused by the weight of the forklift and hydraulically induced forces are exerted on the frame at this mounting location. This can eventually cause damage to the frame or even cause failure of the frame. Moreover, the latches provided on the end of the trailer requires the corresponding bars to be positioned at a particular location on the frame of the forklift so that the forklift will be in proper orientation when it is mounted for transport. This limits the variety of forklifts that can be mounted to a particular trailer since the geometric and angular shape of the frame on each forklift differs. Thus, the trailer and the forklift must then be used as a matched pair severely limiting the utility of the trailer. Lastly, such prior art mounting systems can not be readily used in a variety of carrier vehicles because the extension of the beds relative to the frame (i.e. extension of the bed beyond the frame) also varies widely between carrier vehicles.
Therefore, there still exists a need for a mounting system for mounting a vehicle mounted forklift on a carrier vehicle such as a trailer which will avoid the disadvantages of the prior art mounting systems. In particular, there still exists a need for such a mounting system that will be easier to use so that mounting can occur more quickly and consistently. In addition, there exists a need for such a mounting system that will minimize the distance the forks must be advanced so that the stresses and strains on the various components of the lift and advancing mechanisms can correspondingly be minimized. Furthermore, there still exists a need for such a mounting system that will minimize the forces exerted on the frame of the forklift. Moreover, there exists a need for such a mounting system which can be used with a variety of forklifts thereby increasing the utility of the trailer. Lastly, there still exists a need for such a mounting system which can be used with a variety of carrier vehicles.
In view of the foregoing, it is an object of the present invention to provide an improved mounting system for mounting a vehicle mounted forklift on a carrier vehicle such as a trailer that will be easier to mount than the prior art mounting systems.
A second object of the present invention is to provide such a mounting system that will minimize the distance the forks must be advanced during mounting so that the stresses and strains on the various components of the lift and advancing mechanisms can also be minimized.
Yet another object of the present invention is to provide such a mounting system that will minimize the forces exerted on the frame of the forklift.
A fourth, it is an object of the present invention to provide such a mounting system which can be used with a variety of forklifts thereby increasing the utility of the trailer.
Still further, it is an object of the present invention to provide such a mounting system which can be used with a variety of carrier vehicles.
In accordance with the present invention, these objects are obtained by an improved mounting system for mounting a forklift on a carrier vehicle where the forklift includes a frame, a mast connected to the frame, and a fork carriage having a pair of forks extending therefrom. The fork carriage is adapted to be vertically displaceable on the mast and laterally extendable relative to the mast as well. The carrier vehicle for mounting the forklift includes a mounting end with at least one fork receiver adapted to receive the pair of forks therein and to allow complete lifting of the forklift off of a ground surface by vertically displacing the fork carriage. In accordance with the present invention, at least one hook is attached to either the mast of the forklift or the mounting end of the carrier vehicle, and an engagement bar is secured to the other of the mast or the mounting end. The engagement bar is sized to be received within the at least one hook to thereby securely mount the forklift to the mounting end of the carrier vehicle.
In one preferred embodiment of the present invention, the mast includes base portions which are pivotally attached to the frame of the forklift. Preferably, the at least one hook is two hooks rigidly attached to the base portions of the mast, the two hooks being open downwardly. In addition, the engagement bar is secured to the mounting end of the carrier vehicle. In this regard, in accordance with the preferred embodiment, the engagement bar is adapted to be laterally extendable from the mounting end. Preferably, the engagement bar is attached to a pair of horizontal members which are slidingly received within a pair of slot compartments that are attached to the mounting end of the carrier vehicle. In addition, the pair of horizontal members and the pair of slot compartments include at least one through hole adapted to receive a locking means for securing the horizontal members within the pair of slot compartments. In one embodiment, the locking means is either a fastener or a pin.
In yet another alternative embodiment of the present invention, the two hooks are secured to the mounting end of the carrier vehicle, and the engagement bar is attached to the base portion of the mast. Like the previous embodiment, the two hooks are adapted to be laterally extendable from the mounting end. In this regard, each of the two hooks are attached to horizontal members which are slidingly received within the slot compartments that are attached to the mounting end of the carrier vehicle. The pair of horizontal members and the pair of slot compartments may include at least one through hole adapted to receive at least one of a fastener and a pin to thereby secure the horizontal members within the slot compartments.
These and other objects, features and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments of the invention when viewed in conjunction with the accompanying drawings.